/*
 * Copyright 2002-2015 the original author or authors.
 * 
 * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except
 * in compliance with the License. You may obtain a copy of the License at
 * 
 * http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software distributed under the License
 * is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express
 * or implied. See the License for the specific language governing permissions and limitations under
 * the License.
 */
package org.huihoo.ofbiz.smart.session;

import java.util.Set;

/**
 * Provides a way to identify a user in an agnostic way. This allows the session to be used by an
 * HttpSession, WebSocket Session, or even non web related sessions.
 *
 * @author Rob Winch
 * @since 1.0
 */
public interface Session {

  /**
   * Gets a unique string that identifies the {@link Session}
   *
   * @return a unique string that identifies the {@link Session}
   */
  String getId();

  /**
   * Gets the Object associated with the specified name or null if no Object is associated to that
   * name.
   *
   * @param attributeName the name of the attribute to get
   * @return the Object associated with the specified name or null if no Object is associated to
   *         that name
   * @param <T> The return type of the attribute
   */
  <T> T getAttribute(String attributeName);

  /**
   * Gets the attribute names that have a value associated with it. Each value can be passed into
   * {@link org.springframework.session.Session#getAttribute(String)} to obtain the attribute value.
   *
   * @return the attribute names that have a value associated with it.
   * @see #getAttribute(String)
   */
  Set<String> getAttributeNames();

  /**
   * Sets the attribute value for the provided attribute name. If the attributeValue is null, it has
   * the same result as removing the attribute with
   * {@link org.springframework.session.Session#removeAttribute(String)} .
   *
   * @param attributeName the attribute name to set
   * @param attributeValue the value of the attribute to set. If null, the attribute will be
   *        removed.
   */
  void setAttribute(String attributeName, Object attributeValue);

  /**
   * Removes the attribute with the provided attribute name
   * 
   * @param attributeName the name of the attribute to remove
   */
  void removeAttribute(String attributeName);
}
